Can i duplicate this Hallway then join it on end of current hall at a 45deg angle as a continuous (short video of render in post)?
Here's a way you could do it.

Duplicate the hallway, select the duplicate, go into edit mode, select this face:


and then press A to select all faces. This is now the active face.

Change your snap settings to Vertex and make sure Active and Move are selected.



Press G and then X or Y depending on how the hallway is aligned, then either press CTRL if snapping is disabled or enable snapping with shift+tab. Drag the duplicate hallway until it snaps to the original hallway.



Press 2 to go into edge select mode, select the edge pictured below, and press shift+s, the choose Cursor to Selected.



Change your pivot point to 3D Cursor.



Change snapping back to increment and rotate the duplicate hallway around Z by 45 or 90 or whatever degrees.



Now you have lots of options. Here are two. In object mode select both hallways and then go into edit mode. Select the inner edge loops of the hallways and select Bridge Edge Loops from the right-click menu or from the Edge menu dropdown. Do the same for the outer loops.



Alternatively, you could use the spin tool.



You could add additional offsets to the hallways to make the curve more gradual, or whatever.